Choosing the Proper Tank

[dsddcd]

So I am trying to figure out where I can buy a tank but I have some questions.

I was planning on using a HDPE tank are there any problems with it using a 50/50 mix of water and methonal?

What is the recomneded NPSH for the pump?

Has anyone tried a foam baffle similar to the material used in fuel tank?

To prevent cavitation or more importantly bubbles from entering the line does anyone use a surge tank?